Answer:
The required angle is (90-25)° = 65°
Explanation:
The given motion is an example of projectile motion.
Let 'v' be the initial velocity and '∅' be the angle of projection.
Let 't' be the time taken for complete motion.
Let 'g' be the acceleration due to gravity
Taking components of velocity in horizontal(x) and vertical(y) direction.
= v cos(∅)
= v sin(∅)
We know that for a projectile motion,
t =
Since there is no force acting on the golf ball in horizonal direction.
Total distance(d) covered in horizontal direction is -
d = ×t = vcos(∅)× = 
.
If the golf ball has to travel the same distance 'd' for same initital velocity v = 23m/s , then the above equation should have 2 solutions of initial angle 'α' and 'β' such that -
α +β = 90° as-
d = 
= ![\frac{v^{2}sin(2[90-β]) }{g}](https://tex.z-dn.net/?f=%5Cfrac%7Bv%5E%7B2%7Dsin%282%5B90-%CE%B2%5D%29%20%7D%7Bg%7D)
=
= 
.
∴ For the initial angles 'α' or 'β' , total horizontal distance 'd' travelled remains the same.
∴ If α = 25° , then
β = 90-25 = 65°
∴ The required angle is 65°.
Since the horizontal velocity is what is doubled, that does not affect the fall of the ball, thus the fall is still 5 seconds long.
Question 24.
The Environmental Protection Agency is a regulatory agency that protects human and environmental life. Because it is a regulatory agency, it oversees all actions that has a direct effect on the environment. Letter A could be an answer, but not the best. The EPA does not trust environmentalists because they still have to inspect the ship. Maybe the ship would drive away fishes from their aquatic homes which would cause an imbalance in the ecosystem. So, the best answer would be letter C.
Question 25:
Gravity is a force of attraction that acts as the pull towards the object's center. According to Newton's Law of Universal Gravitation, the force of gravity is directly proportional to the mass, and inversely proportional to distance. The heavier and nearer the objects are, the greater the force of gravity. Every object in the world is acted upon by gravity, whether at rest or moving. Therefore, the answer is <span>B.
Question 26:
Power is the amount of work done per unit time. So, if time is not changed and work increases, the power will have to increase as well. The answer is C.
Question 27:
In electricity, the power of the load in a circuit is equal to the product of its voltage and current. Therefore, voltage and current are directly proportional to power. But they are inversely proportional to each other. So, if voltage increases, the power also increases. Therefore, the answer is B.
Question 28:
Hybrid cars work on the energy both coming from oil and electricity. Electricity is a more expensive fuel than oil. So, you will expect that hybrid cars are much more expensive. Electricity comes from batteries, which is made up of electrolyte solutions of metals. They are non-renewable source as well. The only advantage is that, batteries do not emit pollutant gases unlike oil. These gases deteriorate the ozone layer which protects the Earth from exposure to UV rays. Therefore, the answer is B.</span>
Answer:
The percent of power extended against sea-level air drag is 50.15%
Explanation:
Length L is 22 ft, Power P is 590 hp,
Speed of air V = 175 mi/h. To convert to ft, we will multiply by 1.46
V = 175 × 1.46 = 255.5 ft
Frontal Area A is given as 23.5 ft
Coefficient of drag, Cd is 0.35
From text, Density of Air at sea level ρ = 0.00237 slug/ft³
The formula for calculating Drag Force F is
F = Cd × 
× ρAV²
Substitute the values above into the formula
F = 0.35 × × 0.00237 × 23.5 × 255.5²
= 0.35 × × 3635.78
= 636.26 lbf
But Power P = FV
Therefore we substitute for F and V to get P
P = 636.26 × 255.5
= 162564.43 ft.lbf/s
To convert to horsepower, we multiply by 0.00182 hp
= 162564.43 × 0.00182
= 295.87 hp
The percent of power extended against sea-level air drag is
= (295.87/590) × 100
= 50.15%
